This proposal is an application for the renewal of National Institutes of Health Grant HL 11119, the purpose of which is to make available an effective common amino acid analysis and automatic protein sequencing operation for nine research groups in the Departments of Biochemistry and Molecular Biology, Biological Sciences and Chemistry. The request is for support for a suitable operator of the facility and for supplies and maintenance of the equipment. With the acquisition of a second Durrum D-500 amino acid analyzer and a Beckman Model 890C sequencer it became essential to have an operator of the entire set of instruments of a considerably more sophisticated quality than previously required. This has made it possible to maintain, run and improve the instrumentation in an efficient and satisfactory manner as well as adapt it to the special research needs of the investigators. This laboratory now provides strong backing for any protein structure and related studies needed to support the research efforts of the participating investigators. The present research projects dependent on these facilities include: mechanisms of enzyme catalysis (M.L. Bender); structure of LDH-X (E. Goldberg); synthetic polymers with catalytic activities and comparative biochemistry of oxygen-carrying proteins (I.M. Klotz); characterization of protein components of photoreceptor complexes isolated from photosynthetic systems (P.A. Loach); proteins and proteolytic enzymes of coagulative processes (L. Lorand); mitochondrial metabolic role of cytochrome c and antigenicity of globular proteins (E. Margoliash); biosynthesis of bacterial cell wall components (F. Neuhaus); structure, function and mechanism of porphobilinogen synthase (D. Shemin); mechanism of action and design of antitumor agents (R.B. Silverman). These studies are supported by the Public Health Service and the continued existence of a joint amino acid analysis and sequencer operation in the most economical way of providing for their prosecution while obviating duplication of efforts and its resultant inefficiency.